Telescopic crane boom



Feb. 13, 1968 R. JOHNSTON ET L 3,368,696

TELESGOPIC CRANE BOOM Filed Oct. 17, 1966 5 Sheets-Sheet 1 I 'II 24WWW!!! HIIIIIIHIIIIIIHHIIHH nulmuumnmmm Feb. 13, 1968 R. JOHNSTON ET AL3,368,696

TELESCOPI C CRANE BOOM 5 Sheets-Sheet 5 Filed Oct. 1'7, 1966 5 e 0 m W N5 E w Wm o mJa i m m 2 N 0 m k w m. 3 w v m Feb. 13,1968 RLJOHNSTON ETAL3,368,696

TELESCOPIC CRANE BOOM //v vzwmps P065? 1. Joy/vs m/v Maw/714 Q fksu/voATTORNEY Feb. 13, 1968 JOHNSTON ET AL TELESCOPIC CRANE BOOM 5Sheets-Sheet 5 Filed Oct. 1'7, 1966 .09} w w w mvwvn N y! 2 NM m 9 0% 7N E MM u, 5

United States Patent 3,368,696 TELESCOPIC CRANE BOOM Roger L. Johnstonand Kenneth 0. Freund, Fort Dodge, Iowa, assignors to SargentEngineering Corporation, Fort Dodge, Iowa, a corporation of Iowa FiledOct. 17, 1966, Ser. No. 587,053 6 Claims. (Cl. 21259) This inventionrelates generally to a multiple section hydraulically extendible boomstructure for a crane or the like and in particular to a power-operatedtelescoping outermost or fly section for such a boom structure and themethod for power extending and retracting the fly section.

In telescoping boom structures having lengths in the neighborhood offrom eighty feet to one hundred feet and capable of handling loads ofabout forty tons it is desirable that the boom sections be of a requiredstrength with a minimum of weight. It is further desirable that the boomsections be successively telescopically receivable one within another soas to reduce the over-all length of the boom for transport purposes to alength substantially equal to the length of the innermost .or basesection of the boom.

In boom structures having the above requirements, and because of spaceand weight limitations, all of the boom sections except the outermost orfly section, are operatively associated with a linearly extendible powermeans, usually a hydraulic cylinder and piston assembly, providing forthe extension and retraction of a section relative to a next adjacentinner section. When the fly section is to be used it is now the usualpractice, and while the boom is retracted and in a lowered horizontalposition to manually, directly or through mechanical means, extend thefly section from the next adjacent section and then connect such twosections against relative longitudinal movement. In use, therefore, thefly or outermost section functions as a fixed forward extension for thenext adjacent inner section. After use and with the boom retracted andin a lowered horizontal position the fly section is mannually returnedto a retracted position within the next adjacent boom section.

An object of this invention is to provide an improved multi-sectionhydraulic extensible boom for a crane or the like.

Another object of this invention is to provide an improved method forextending and retracting the fly section of a multi-sectionhydraulically extendible boom structure.

A further object of this invention is to provide a telescopic boomwherein the fly section is power-operated to extended and retractedpositions therefor.

Stiil a further object of this invention is to provide a telescopic boomhaving an inner section, a mid-section and an outer or fly sectionwherein the power means for extending and retracting the mid-sectionrelative to the inner section is also utilized to extend and retract thefly section relative to the mid-section.

Another object of this invention is to provide a telescopic boom havingan inner section, a mid-section and a fly section wherein a linearlyextendible power means positioned within the fly section, when all threesections are telescopically retracted, has one end connected to theinner end of the inner section. The opposite end of the power means isconnected to a coupling member slidably mounted for longitudinalmovement within the fly section for detachable connection with the outerend of the fly section to provide for the power means retracting andextending the fly section relative to the mid-section, and fordetachable connection to the inner end of the fly section and to theouter end of the mid-section to provide for the power means retractingand extending the mid- 3,368,695 Patented Feb. 13, 1968 section relativeto the inner section with the fly section extended from the mid-section.

Further objects, features and advantages of this invention will becomeapparent from the following description when taken in connection withthe accompanying drawings wherein:

FIG. 1 is a perspective view of a mobile crane incorporating the boomstructure of this invention and wherein the boom is illustrated inretaracted transport position;

FIG. 2 is a reduced perspective view of the mobile crane in FIG. 1showing the boom structure in extended operating position;

FIG. 3 is an enlarged foreshortened longitudinal sectional view of theboom structure with the sections thereof in retracted positions;

FIG. 4 is a transverse sectional view taken on the line 44 in FIG. 3;

FIG. 5 is an enlarged transverse sectional view as seen on the line 55in FIG. 3;

FIG. 6 is a horizontal longitudinal sectional view of the outer end ofthe boom structure showing the fly section connected for retraction andextension relative to a next adjacent inner section;

FIG. 7 is illustrated similarly to FIG 6 and shows the fly sectionconnected to and extended from the next adjacent inner section formovement therewith;

FIG. 8 is a vertical longitudinal sectional view of the outer end of theboom showing the fly section connector for movement relative to the nextadjacent inner section;

FIG. 9 is illustrated similarly to FIG. 8 and shows the fly sectionconnected to and extended from the next adjacent inner section formovement therewith;

FIG. 10 is illustrated similarly to FIG. 8 and shows the relativearrangement of those parts of the boom structure providing for aretraction of the outermost or fly section; and

FIG. 11 is a perspective view of a coupling member forming part of thestructure providing for the power operation of the fly section toextended and retracted positions therefor.

Referring to the drawings there is illustrated in FIGS. 1 and 2 a cranevehicle 15 which includes the boom structure 16 of this invention.Mounted on the frame 17 of the vehicle 15 are hydraulically operatedOutriggers 18. When the crane is to be operated the Outriggers 18 areadjustable laterally outwardly of the vehicle frame 17 and then extendedinto engagement with the ground to remove a part of the load from thevehicle frame 17 so as to cooperate with the vehicle wheels 19 instabilizing the vehicle frame 17 against lateral and verticalHIOVCITKEUIS.

A turntable 21 carried at the rear end of the vehicle frame 17 rotatablysupports a base frame 22 for 360 horizontal rotation relative to thevehicle frame 17. The boom structure 16 is pivotally mounted on the baseframe 22 for pivotal up and down movement by a pair of hydrauliccylinder assemblies 23 shown best in FIG. 2. Also mounted on the baseframe 22 is an operators cab 24- and a power plant, indicated generallyat 26, for rotating the base frame 22, for operating oil pumps (notshown) to supply oil under pressure to a hydraulic motor 27 forming partof a winch unit 28 that is supported on the rear end of the boomstructure 16, and to a hydraulic motor (not shown) for supplying oilunder pressure to hydraulic cylinder assemblies, to be later described,for extending and retracting the boom structure 16.

In transport, and as shown in FIG. 1, the retracted boom structure 16 isextended horizontally and longitudinally of the vehicle frame 17. Adrivers cab 29 and a power unit 31 for driving the vehicle 15 aremounted at the front end of the vehicle frame 17 below and in aclearance relation With the boom structure 16. To counteract theoverhanging weight of the boom structure the base frame 22 is providedwith a counterbalance 32.

Referring to FIGS. 2 and 3 the boom structure 16 is shown as comprisedof four tubular sections, namely, a base or inner most section 33 of arectangular shape in transverse section, and an outermost or fly section34 and intermediate sections 36 and 37 of substantially square shapes intransverse section. The sections 36 and 37 will hereinafter be referredto as a first inner section and a second inner section, respectively. Asshown in FIGS. 1 and 3 the boom sections, from the fly section 34inwardly, are successively telescopically received one within another sothat the boom structure 16, when retracted, has a length which is alittle longer than the length of the base section 33.

The base section 33 is of a size in transverse cross section to receivetherein the first inner boom section 36 and a lineally extendible powermeans 38, illustrated as a hydraulic cylinder assembly, having acylinder 39 and a piston rod 41. The cylinder assembly 38 is extendedlongitudinally of the base section 33 at a position above the firstinner section 36-. The closed or rear end of the cylinder 39 ispivotally connected at 42 to the rear or inner end of the base section33 with the free end of the piston rod 41 pivotally connected at 43 tothe outer or forward end of the top wall 45 of the first inner section36.

A second lineally extendible power means 44, also illlustrated as ahydraulic cylinder assembly, and including a cylinder 46 and a pistonrod 47 is located interiorly of the fiy section 34, when the fly sectionis retracted within the second inner boom section 37. The closed or rearend of the cylinder 46 is pivoted at 48 to the rear end of the firstinner section 36 with the free end of the piston rod 47 pivotallyconnected by a pin 49 to the rear end of an elongated coupling member 51located within and slidable longitudinally of the fly section 34 for apurpose to appear later.

To provide for a free guided relative longitudinal movement between theadjacent sections of the boom structure 16 the first inner section 36 onits top side 45 and adjacent the rear end thereof carries a pair oftransversely opposite pivotally supported bearing plates 53 arranged toopposite sides of the cylinder assembly 38 and adapted for contactengagement with the underside of the top wall 54 of the base section 36.Secured to the forward or outer end of the bottom wall 56 of the basesection 33 is a bearing plate 57 for contact engagement with theunderside of the bottom wall 58 of the first inner section 37. Verticalclearance between the inner sections 36 and 37 is maintained by abearing plate 59 secured to the rear end of the top Wall 61 of thesecond inner section 37 for contact engagement with the underside of thetop wall 45 of the first inner section 36. A bearing plate 62 mounted atthe front end of the bottom wall 63 of the first inner section 36 isadapted for contact engagement with one underside of the bottom wall 64of the second inner section 37. The fly section 34 has a bearing plate66 adjacent the rear end of its top wall 67 for contact engagement withthe underside of the top wall 61 of the second inner section 37. Abearing plate 68 at the front end of the bottom wall 64 of the secondinner section 37 is adapted for contact engagement with the bottom wall69 of the fly section 34.

To provide lateral clearance between the boom sections during relativelongitudinal movement therebetween each of the side walls 71, 72, and 73of the sections 36, 37 and 34, respectively (FIG. 4), has adjacent itsrear end a bearing plate 74 extended laterally outwardly therefrom forcontact engagement with the inner surface of a next adjacent side wallof a boom section.

A load lifting cable 78 from the winch unit 28 (FIG. 1) is extendedthrough the base section 33 (FIG. 3) at a position above the cylinderassembly 38 for travel over pulleys 79 and 81 mounted at the outer endsof the top walls 45 and 61 of the inner sections 36 and 37,respectively. From the pulley 81 the cable 78 is trained over pulleys 82and 83 supported on a block unit 84 secured to and projected forwardlyfrom the outer end of the fly sections 34. The terminal end of the cable78 carries a usual crane hook 85.

The coupling member 51 (FIGS. 10' and 11) includes a pair of likeupright side plates 84. The opposite ends of each plate 84 terminate inapex or triangular sections 86 and 87. For convenience the end sections86 and 87 of a plate 84 will be referred to as the front and rear endsections, respectively, of the coupling member 51. The plates 84 areconnected together intermediate their upper and lower edges by ahorizontal longitudinally extended plate member 88. Spacedlongitudinally of the upper and lower edges of the plates 84 and securedthereto are transversely extended bearing members 89 adapted for contactengagement with the inner surfaces of the top wall 67 and bottom wall 69of the fly section 34. Extended laterally outwardly from each side plate84 are longitudinally spaced bearing blocks 91 for contact engagementwith the inner surfaces of the side walls 73 of the fly section 34. Thecoupling member 51 is thus guidably supported for slidable movementlongitudinally of the fiy section 34.

The pin 49 which pivotally connects the free end of the piston rod 47 ofthe cylinder assembly 44 to the coupling member 51 is extended betweenand rotatably supported on the rear apex sections 87 of the side plates'84. The apices of the front apex sections 87 of the side plates 84 areformed with transversely aligned openings 92. Rear wardly of theopenings 92 the side plates 84 are formed with transversely aligned ovalshaped openings 93 (only one of which is shown) for receiving theopposite ends of a transversely extended tubular member 94 which is ofan oval shape in transverse section corresponding to the oval shape ofthe openings 93. The tubular member 914 is secured along its rear edge,as by welding, to the front edge of the connecting plate 88 and has theend surfaces thereof flush with the outer surfaces of the side plates84.

The coupling member 51 constitutes a forward extension of the cylinderassembly 44 and provides for the assembly 44 being utilized as a commonpower means for extending and retracting the fly section 34 relative tothe second inner section 37 and for extending and retracting the secondinner section 37 relative to the first inner section 36 when the flysection 34 is connected to and extended from the second inner section37.

In the operation of the boom structure 16 assume the sections thereof tobe in their relatively retracted positions as indicated in FIG. 8 forthe front end portions thereof. This retraction of the boom during roadtravel of the vehicle 15 is maintained, in conjunction with theretracted cylinder assemblies 38 and 44, by an eye pin 96 insertedthrough openings 97 and 98 provided at the forward ends of the top walls45 and 61 of the inner sections 36 and 37, respectively. The fly section34 is connected to the coupling member 51 by a pull-out pin 99 extendedthrough openings 101 (FIG. 6) formed in the side walls 73 of the flysection and the openings 92 at the front ends 86 of the coupling memberside plates 84.

When the boom structure 16 is to be used it is desirable that the flysection 34 be initially extended from the second inner section 37. Withthe boom structure 16 retracted and extended horizontally this isaccomplished by extending the cylinder assembly 44 to its full length.Such initial extension of the cylinder assembly 38 moves the fly section34 and attached coupling member 51 from their full line positions shownin FIG. 8 to their dotted line positions shown in the same figure.During this extension of the fly section 34 outwardly from the secondinner section 37 the eye pin 96 is retained in place to prevent anyforward movement of the second inner section 37. After the fly section34 has been extended the pin 99 is withdrawn and the cylinder assembly44 retracted whereby the coupling member 51 is pulled inwardly of thefly section 34 from its dotted line position shown in FIG. 9'to its fullline position shown in the same figure. In this full line position thecoupling member 51 has the tube 94 at the front end thereof in axialregistration with transversely opposite holes 103 (FIG. 7) formed in theforward ends of the side walls 72 of the second inner section 37- andholes 104 at the rear ends of the side walls 73 of the fly section 34. Aconnecting pin 105 (FIG. 9) is then inserted through the alignedopenings 103 and 104 and the tube 94 to conmeet the coupling member 51with both of the sections 34 and 37. The eye pin 96 is then removed fromthe inner sections 36 and 37.

The boom structure 16 may then be pivotally raised and lowered withlater actuation of the cylinder assembly 44 providing for the extensionof the second inner section 37 relative to the first inner section 36,with the fly section constituting a fixed forward extension for thesecond inner section 37. On actuation of the cylinder assembly 38 thefirst inner section 36 is extended from the base section 33 with thesections 37 and the fly section 34 being movable therewith as a unit.

When the boom structure 16 is to be retracted for transport purposes thefirst inner section 36 is retracted within the base section 33 and thesecond inner section 37 within the first inner section 36. The boom'isthen lowered to a horizontally extended position, and the pin 105withdrawn so that on extension of the cylinder assembly 44 the couplingmember 51 is moved from its full line position in FIG. 9 to its dottedline position shown in the same figure. At this moved position of thecoupling member 51 the front ends 86 of the plates 84 are in abuttingengagement with a stop member 102 located adjacent the front end of thefly section 34 and secured to and extended between its side walls 73.This engagement between the coupling member 51 and the stop member 102aligns the openings 101 in the fly section 34 with the openings 92 inthe coupling member. The pull-out pin 99 is then inserted within suchaligned openings and the cylinder assembly 44 is retracted to in turnretract the fly section 34 within the second inner section 37. Theretracted position of the second inner section 37 within the first innersection 36, is limited by a stop member 106 provided adjacent the rearend of the first inner section 36 for abutting engagement with the rearend of the second inner section 37. This engagement aligns the openings97 and 98 in the sections 36 and 37, respectively, to receive the eyepin 96 for holding these two sections against relative longitudinalmovement.

It is seen therefore thatthe invention provides for a hydraulicallyextendible boom structure 16 wherein the boom sections 34, 36 and 37 areretractable and extendible by power means and wherein the cylinderassembly 44 is selectively connectible through the coupling mem ber 51and pins 99 and 105 to the fly section 34 alone, or to the sections 37and 34 when the fly section 34 is projected from the second innersection 37.

The alignment of the openings 103 and 104 in the sections 37 and 34,respectively, with the tube 94 to receive the pin 105, following theextension of the fly section 34 from the section 37 is facilitated bythe connection of the two inner sections 36 and 37 by the eye pin 96. Itis also to be noted that the insertion of the pin 105, to connect thesections 34 and 37 with the coupling member is facilitated by the ovalshape of the tube 94.

Although the invention has been described with respect to a preferredembodiment thereof it is to be understood that it is not to be solimited since changes can be made therein which are within the fullintended scope of this invention as defined by the appended claims.

We claim:

1. A telescopic hydraulically extensible boom for a crane or the likehaving at least three sections comprising:

(a) a first section,

(b) a second section telescopically received in the first section,

(c) a fly section telescopically received in the second section,

(d) a linearly extendible power means positioned interiorly of said flysection, when the fly section is telescoped within said second section,and connected at one end to the inner end of said first section, and

(e) means for detachably connecting the opposite end of said power meanseither to the outer end of said fly section or to the inner end of saidfly section and the outer end of said second section.

2. A telescopic boom for a crane or the like having at least threesections comprising:

(a) an inner section,

(b) a mid-section,

(c) an outer section,

(d) said mid-section telescopically received within said inner sectionand said outer section telescopically received within said mid-section,

(e) a linearly extended power means positioned interiorly of said outersection with one end projected through the inner end of the mid-sectionfor connection to the inner end of the inner section, and

(f) coupling means connected to the opposite end of said power meansmovable longitudinally of and within said outer section connectableeither to said outer section alone or to both said outer section andmid-section, when the outer section is extended from said mid-section,

(g) said outer section, when connected alone to said coupling means,being linearly movable to extended and retracted positions relative tosaid mid-section by said power means and, when connected to saidmid-section by said coupling means being movable with said mid-sectionrelative to said inner section by said power means.

3. A telescopic boom for a crane or the like having at least threesections comprising:

(a) an inner section,

(b) a mid-section telescopically received within said inner section,

((1) an outer section telescopically received within said mid-section,

(d) a linearly extendible power means positioned longitudinally of andwithin said outer section with one end connected to the inner end ofsaid inner section,

(e) a coupling member slidably mounted for longitudinal movement Withinsaid outer section and connected to the other end of said power means,and

(f) means for detachably connecting said coupling member to the outerend of said outer section to provide for the extension and retraction ofsaid outer section relative to said mid-section by said power means, orto the inner end of said outer section and to the outer end of saidmid-section to provide for said mid-section and outer section beingmoved together by said power means relative to said inner section.

4. A telescopic boom for a crane or the like having at least threesections comprising:

(a) a tubular inner section,

(b) a tubular mid-section telescopically received within said innersection,

(c) a tubular outer section telescopically received within saidmid-section,

(d) a linearly extendible and retractable hydraulic cylinder assemblyextended longitudinally within said outer section with one end projectedtherefrom and connected to the inner end of said inner section,

(e) an elongated coupling member slidably mounted within the outersection and connectable to the opposite end of said hydraulic assembly,

(f) a first means for detachably connecting said coupling member only tosaid outer section for extension and retraction of said outer sectionrelative to said mid-section in response to extension and retraction ofsaid hydraulic assembly, and

(g) a second means, when said first connecting means is disconnected andsaid outer section is extended from said mid-section, for connectingsaid mid-section and outer section to said coupling member for movementtogether relative to said inner section in response to extension andretraction of said hydraulic assembly.

5. The telescopic boom according to claim 4 wherein:

(a) said mid-sectionis formed with a pair of transversely oppositealigned openings adjacent the front end thereof, said outer section isformed with a pair of transversely opposite aligned openings adjacenteach end thereof, and said coupling member at the end thereof remotefrom said hydraulic cylinder assembly having a pair of longitudinallyspaced transversely extended openings,

(b) said first connecting means comprising pin means insertable withinthe openings at the outer end of said outer section and one of theopenings in said coupling member, when said outer section is retractedwithin said mid-section, and

(c) said second connecting means comprising pin means insertable withinthe other opening in said coupling member, the openings in saidmid-section and the openings adjacent the inner end of said outersection, when the outer section is extended from said mid-section.

6. The method for extending and retracting the fly section of atelescopic boom having at least three sections wherein the fly sectionis telescopically received in a midsection and the mid-section istelescopically received in an inner section comprising:

(a) arranging a linearly extendible power means within the flysectionwith one end connected to the inner end of the inner section and anopposite end detachably connectable with the outer end of the flysection when the fly section is telescoped within the mid-section,

(b extending the power means to extend the fly section from themid-section, and disconnecting the opposite end of the power means fromthe outer section,

(0) retracting the power means and detachably connecting the oppositeend thereof to the outer end of the mid-section and to the inner end ofthe fly section so that subsequent retraction and extension of the powermeans will extend and retract the mid section relative to the innersection with the fly section constituting a forward extension of saidmidsection,

((1) retracting the mid-section relative to the inner section anddisconnecting the opposite end of the power means from the outer end ofthe mid-section and the inner end of the fly section,

(e) extending the power means relative to the mid-section and flysection to position the opposite end of the power means at the outer endof the fly section, and

(t) then detachably connecting the opposite end of the power means tothe outer end of the fly section and retracting the power means totelescope the fly section within the mid-section.

References Cited UNITED STATES PATENTS 2,571,858 10/1951 Garland 2122,668,625 2/1954 Garland 21255 3,300,060 1/1967 Lado 21255 ANDRES H.NIELSEN, Primary Examiner.

1. A TELESCOPIC HYDRAULICALLY EXTENSIBLE BOOM FOR A CRANE OR THE LIKEHAVING AT LEAST THREE SECTIONS COMPRISING: (A) A FIRST SECTION, (B) ASECOND SECTION TELESCOPICALLY RECEIVED IN THE FIRST SECTION, (C) ALINEARLY EXTENDIBLE POWER MEANS POSITIONED INSECTION, (D) A LINEARLYEXTENDIBLE POWER MEANS POSITIONED INTERIORLY OF SAID FLY SECTION, WHENTHE FLY SECTION IS TELESCOPED WITHIN SAID SECOND SECTION, AND CONNECTEDAT ONE END TO THE INNER END OF SAID FIRST SECTION, AND (E) MEANS FORDETACHABLY CONNECTING THE OPPOSITE END OF SAID POWER MEANS EITHER TO THEOUTER END OF SAID FLY SECTION OR TO THE INNER END OF SAID FLY SECTIONAND THE OUTER END OF SAID SECOND SECTION.